Stoker



sToKER Filed July 25, 1940 Feb'. 1(519435 s. A. TowNsEND, JR

2 sheets-sheet 1 Z4, fr rgl 46 47 i FIGA. r SAMUEL A.TowNsENDJ BY 5 7b l I ATTORNEY.

Feb. 16, 19.43.

` S. A. TOWNSEND, JR

STOKER Fired July .25,f'194o-A FIG.6.

Patented Feb. 1e, 1943 AUNITED STATES PATENT OFFICE STOKER Samuel A: Townsend, Jr., .Webster Groves, Mo. Application July 25, 1940, Serial No. 347,407

`2 Claims.

This invention relates to automatic stoker devices particularly adapted for domestic use. f

Coal feeding stokers of the Vhousehold or domestic type, for use with bituminous or other relatively fast burning solid fuels, must be constructed to maintain a relatively kdeep bed o f coals in order to insure holding of the' fire Vdur- Cil ing substantial periods when the drafts are re duced and less heat is required. Ordinarily, a

therefor, and manual grates are frequently provided at the sides for desirablyA extending the bed of coals. These devices require frequent attention to the grates and removal of clinkers.

It is an object of the present invention toxprovide a more fully automatic stoker of the above type which willmaintain a relatively deep, uniformly'tapered lbed of unconsumed coals, without the necessity of providing the usual manually operable grate extensions, and thus eliminate the usual frequent manual shaking of the grate or removal of accumulated clinkers and ashes in the immediate vicinity of the retort, it being the` intention that the invention may be Vused with a relatively spacious ashpit which requires attention only at very infrequent intervals. Accordingly, a stoker utilizing the present invention approaches substantially closer to the ideal of fully automatic operation than has been the case with stokers heretofore applied to similar use. v

I n the accompanying drawings which illustrate the invention:

Fig. 1 is a diagrammatic representation showing a portion of a hot air furnace and stoker embodying the invention.

may Abe formed in part of suitable refractory materials, these walls forming the usual air heating space I2 which maybe connected by means of pipes I3 to suitable heat discharging registers at remote points. The inner portion of the furnace is connected to a flue |4. The Stoker, gene,

aprons 2|, these aprons and the upper portions of the walls of retort well 2|) being apertured and forming the Yusual tuyres. A sheet metal pan 22 l underlies the retort well and aprons and inclu s sharply inclined side portions 23. The`V ole structure is supportedr on leg'sf, as at 24, resting on the bottom of the furnace'.`

Suitably` journaled adjacent the outer edges of aprons 2| are/a pair of shafts 25 rigidlymountf ing sprockets] 26 and similarly journaled` at some Fig. 2 is a top view ofthe retort and traveling v grate portions of the Stoker.

Fig. 3 is a vertical transverse center section through the retort and showing various operating mechanisms.

Fig. 4 is a vertical transverse sectional view taken substantially though the center of the retort and traveling grate structures, as indicated by the section line on Fig. 3.

Fig. 5 is a top viewshowing a modified form of retort and combination traveling grate and ash conveyor structure.

Fig. l6 is a vertical transverse section of the same taken substantially on the line 6-6 of Fig. 5.

The furnace in Fig. 1 is of the hot air type, though any other type may be used, and com- .prises an'outerwall IIJ and inner wall I, which distance laterally therefrom are additional shafts'2l mounting sprockets 28. Carried on the sprockets 26 and 28 are chain grate structures 29 which extend from immediately beneath .the

outer edges of aprons 2| to the adjacent inner edges of ash pits I6. It is assumed that some ash material will slip through grate structures 29 ontoV inclined pans 23 and this material will slide down these pans and may be removed through doors 3|). These doors are shown yieldingly closed by means of overbalanced, weighted levers 3| which will automatically open to release the ash when suillcientlyaccumulated to vlift'weighted levers 3|. The angle of pans 23,

of course, determines the force available fork operating doors 30.

An air blower is shown at 32 for forcing air through the duct 33 into the air draft space formed between pan portions 22 and 23 and the retort and traveling gratestructures. An under-` feed ram is shown at .34 extending through a chute 35 from a point immediately below hopper 36 to the opposite end of 'retort Well 20. Ram 34 is operated by means of a guide block 36 connected by a pitman 31 to a crank arm 38 which is operated by motor 39 through a suitable chain drive 40 and gear box 4|. A chain 42- connects motor 39 to blower 32.

'Ihe traveling grate structures 29 are operated by means of chains 44 which drive inner journaled shafts 25 through small sprockets 45 and,

at their lower extremities, are connected by means of sprockets 46 to an additional gear box l1. This gear box is, in turn, connected by a sprocket I8 and a chain I3 to a sprocket 50 von the blower shaft. Thus, under-feed ram 3|, air blower 32 and the traveling grate structures are jointly controlled -by .a common motor drive so' as to providefor the feeding of fuel and air at the desired relative rates. The motion of grate structures 29 ls much slower than is the usual case with ordinary ash conveyors or chain grates, this rate of travel being so correlated with the rate at which the coal is fed to the retort well as to maintain a substantial bed of coal which tapers uniformly from the center of the retort well substantially to the outer edges of the traveling grate structure, as indicated at Y in Fig. 4. As air is fed to the entire expanse of these grate structures, unconsumed coals will b'e fully burned before being deposited into the ash pit.

Incase the stoker is shut down, this relatively deep and extensive bed of coals will maintain a fire for a much longer period than would be the case with the use of an ordinary chain grate, as frequently used with large, industrial boilers. This is of particular importance where bituminous coal is used, since such fuel burns substanf tially faster than other, moreV expensive fuels, such as anthracite coal. Moreover, the deep extensive bed of coals provides for adequate heat output for domestic service.,

In Figs. and 6 thc-re is shown a modified form in which the retort well 50 and tuyre forming aprons 5I are surrounded by a pair of concentric, apertured plate structures 52 and 53 supported on bearings 54, 55, 56 and 51, in Vturn carried by legs, Vas at 58, projecting above inclined portions 23 `of the air duct bottom plate structure.V Circular plates 52 and 53 are suitably apertured for the transmission of draft air through the supported bed of coals.

The concentric plates are driven by means of motor 39 -through a suitable gear box Ila, chain 44a, and shaft 25a journaled in bearing supports 56 and 5|. Shaft 25a carries pinions 59 engaging racks 60 and BI, respectively, on plates 52 and 53. Scrapers 62 and 63 are supported above adjacent portions of the traveling plates, as

shown.

The operation of this form is as follows:

Feed ram 34 and apertured plates 52 and 53 are operated at such correlated rates as to maintain a relatively deep bed of unconsumed coals extending from the retort well a substantial distance over the traveling grate structures, as in the previous form. In this case, coals on each plate will be conducted around to the associated scraper B2 or 63 and then diverted outwardly, the size and rate of the plates being such that only fully consumed ash material will be deposited into ash pit I6 by outer scraper 63.

In both forms, the usual daily shaking of the grate for the purpose of dropping ashes into the ash pit is avoided, but at the same time, a relatively deep bed of coals is maintained, as is essen-y tial where bituminous fuel is used. Another ad vantage results from the fact that burning coals are carried by the traveling grate structures outwardly from the retort and thus closer to the air space I2 extending around the furnace, than is the case where a retort alone is used.

Various features may be modified as will occur Vto those skilled in the art and" the exclusive use vof all such modifications as come within the horizontally a substantial distance outwardly therefrom so as to maintain a bed of fuelof substantial depth adjacent said well, means to apply forced draft to said tuyres and said grate structure, driving mechanism for conjolntly operating said under, feed and draft'means and said traveling grate structure, and means for automatically shifting coal from the inner to the outer edges of said grate structure and for removing ashes from the outeredges of the latter.

2. In a stoker, a retort well, means for forcing fuel into said well', apron structure extending outwardly and downwardly from the upper portion of said well, horizontaltraveling grate means extending from said apron structure a substantial distance outwardly whereby coals traveling by gravity down said apron structure will be caused to accumulate in a bed of substantial depth adjacent said well, tuyre forming perforations in the upper portion of said well, in said apron structure, and in said traveling grate means, means for forcing air through said perforations to promote and continue the burning thereof over the entire structure, and stationary Scrapers adjacent said grate means for transferring coals from the inner to the outer edges thereof and for removing ashes from said outer edge.

SAMUEL A. TOWNSEND, J n. 

